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Can Guo <can.guo@oss.qualcomm.com> says: Hi, This series is a follow-up to the earlier TX Equalization enablement series: https://lore.kernel.org/all/20260325152154.1604082-1-can.guo@oss.qualcomm.com In that cover letter, the "Next" section mentioned adding support for UFS v5.0 Attributes qTxEQGnSettings and wTxEQGnSettingsExt, and enabling persistent storage/retrieval of optimal TX Equalization settings. This 2-patch series implements that part. Motivation ========== TX EQTR procedure is required to find the optimal TX Equalization settings for HS Gears (4-6) before changing Power Mode to the target HS Gears. However, TX EQTR procedure introduces latencies to the first Power Mode change. With optimal TX Equalization settings stored in UFS v5.0 Attributes qTxEQGnSettings and wTxEQGnSettingsExt, host software can reuse known-good settings and avoid going through the TX EQTR procedure. Array Attribute Model ===================== qTxEQGnSettings and wTxEQGnSettingsExt are array-type Attributes. Each element in an array-type Attribute is selected by an (Index, Selector) pair. For these two attributes: - Valid Index range: [0, Max HS Gear - 1] - Valid Selector range: [0, 1] This effectively forms a 2-dimensional array. For HS-Gear n, its TX Equalization settings are stored/retrieved at Index (n - 1). Selector is configurable via a module parameter so that platforms can choose the Selector policy that matches their use. Implementation Overview ======================= 1. Introduce a generic helper for 64-bit query attributes: ufshcd_query_attr_qword(). 2. Add TX EQ settings persistence flow: - Read stored settings from qTxEQGnSettings & wTxEQGnSettingsExt. - Decode and populate per-gear TX EQ parameters. - Use Bit[15] in wTxEQGnSettingsExt as validity indication. - Store trained settings back to these attributes for future reuse. 3. Integrate with existing lifecycle: - Retrieve settings during device parameter initialization. - Store settings during shutdown. New Module Parameters ===================== Three module parameters are added for TX EQ settings persistence control: - txeq_setting_sel (default: 0, range: 0..1) Selects which selector value is used when reading/writing qTxEQGnSettings and wTxEQGnSettingsExt. - retrieve_txeq_setting (default: true) Enables/disables retrieving stored TX EQ settings from device attributes during initialization. - store_txeq_setting (default: true) Enables/disables storing last trained TX EQ settings into device attributes during shutdown. Testing ======= Tested on a UFS v5.0 platform: - TX Equalization setting store path, settings were correctly encoded and stored. - TX Equalization setting retrieval path, settings were correctly extracted and reused. - Full TX EQTR procedure was skipped for a given HS Gear when valid TX EQ settings were provided in qTxEQGnSettings & wTxEQGnSettingsExt for the given HS-Gear. Link: https://patch.msgid.link/20260424151420.111675-1-can.guo@oss.qualcomm.com Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> |
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Linux kernel ============ The Linux kernel is the core of any Linux operating system. It manages hardware, system resources, and provides the fundamental services for all other software. Quick Start ----------- * Report a bug: See Documentation/admin-guide/reporting-issues.rst * Get the latest kernel: https://kernel.org * Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst * Join the community: https://lore.kernel.org/ Essential Documentation ----------------------- All users should be familiar with: * Building requirements: Documentation/process/changes.rst * Code of Conduct: Documentation/process/code-of-conduct.rst * License: See COPYING Documentation can be built with make htmldocs or viewed online at: https://www.kernel.org/doc/html/latest/ Who Are You? ============ Find your role below: * New Kernel Developer - Getting started with kernel development * Academic Researcher - Studying kernel internals and architecture * Security Expert - Hardening and vulnerability analysis * Backport/Maintenance Engineer - Maintaining stable kernels * System Administrator - Configuring and troubleshooting * Maintainer - Leading subsystems and reviewing patches * Hardware Vendor - Writing drivers for new hardware * Distribution Maintainer - Packaging kernels for distros * AI Coding Assistant - LLMs and AI-powered development tools For Specific Users ================== New Kernel Developer -------------------- Welcome! Start your kernel development journey here: * Getting Started: Documentation/process/development-process.rst * Your First Patch: Documentation/process/submitting-patches.rst * Coding Style: Documentation/process/coding-style.rst * Build System: Documentation/kbuild/index.rst * Development Tools: Documentation/dev-tools/index.rst * Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst * Core APIs: Documentation/core-api/index.rst Academic Researcher ------------------- Explore the kernel's architecture and internals: * Researcher Guidelines: Documentation/process/researcher-guidelines.rst * Memory Management: Documentation/mm/index.rst * Scheduler: Documentation/scheduler/index.rst * Networking Stack: Documentation/networking/index.rst * Filesystems: Documentation/filesystems/index.rst * RCU (Read-Copy Update): Documentation/RCU/index.rst * Locking Primitives: Documentation/locking/index.rst * Power Management: Documentation/power/index.rst Security Expert --------------- Security documentation and hardening guides: * Security Documentation: Documentation/security/index.rst * LSM Development: Documentation/security/lsm-development.rst * Self Protection: Documentation/security/self-protection.rst * Reporting Vulnerabilities: Documentation/process/security-bugs.rst * CVE Procedures: Documentation/process/cve.rst * Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst * Security Features: Documentation/userspace-api/seccomp_filter.rst Backport/Maintenance Engineer ----------------------------- Maintain and stabilize kernel versions: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * Backporting Guide: Documentation/process/backporting.rst * Applying Patches: Documentation/process/applying-patches.rst * Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git for Maintainers: Documentation/maintainer/configure-git.rst System Administrator -------------------- Configure, tune, and troubleshoot Linux systems: * Admin Guide: Documentation/admin-guide/index.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst * Tracing/Debugging: Documentation/trace/index.rst * Performance Security: Documentation/admin-guide/perf-security.rst * Hardware Monitoring: Documentation/hwmon/index.rst Maintainer ---------- Lead kernel subsystems and manage contributions: * Maintainer Handbook: Documentation/maintainer/index.rst * Pull Requests: Documentation/maintainer/pull-requests.rst * Managing Patches: Documentation/maintainer/modifying-patches.rst * Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst * Development Process: Documentation/process/maintainer-handbooks.rst * Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git Configuration: Documentation/maintainer/configure-git.rst Hardware Vendor --------------- Write drivers and support new hardware: * Driver API Guide: Documentation/driver-api/index.rst * Driver Model: Documentation/driver-api/driver-model/driver.rst * Device Drivers: Documentation/driver-api/infrastructure.rst * Bus Types: Documentation/driver-api/driver-model/bus.rst * Device Tree Bindings: Documentation/devicetree/bindings/ * Power Management: Documentation/driver-api/pm/index.rst * DMA API: Documentation/core-api/dma-api.rst Distribution Maintainer ----------------------- Package and distribute the kernel: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * ABI Documentation: Documentation/ABI/README * Kernel Configuration: Documentation/kbuild/kconfig.rst * Module Signing: Documentation/admin-guide/module-signing.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst AI Coding Assistant ------------------- CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and follow the AI coding assistants documentation before contributing to the Linux kernel: * Documentation/process/coding-assistants.rst This documentation contains essential requirements about licensing, attribution, and the Developer Certificate of Origin that all AI tools must comply with. 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